This invention relates to an apparatus and method for sub-surface Horizontal Directional Drilling (HDD). HDD is utilized to create an underground pathway without excavation. An example of HDD may be found in U.S. Pat. No. 5,242,026 to Deken, et al., which is incorporated herein by reference in its entirety. One type of apparatus utilized in HDD is a borehole cutter, also known as a “reamer.” An example of a reamer may be found in U.S. Pat. No. 6,386,302 to Beaton, which is incorporated herein by reference in its entirety. In various embodiments, reamers employ a plurality of rotary cone drill bits, such as is disclosed, for example in U.S. Pat. No. 5,421,423 to Huffstutler, which is incorporated herein by reference in its entirety.